1. Field of the Invention
The present invention relates to a liquid crystal display device of external type in which a reflector is placed on the outer surface side of a liquid crystal panel.
2. Description of the Related Art
Regarding cellular phones and portable data terminals at present, liquid crystal display devices are mounted on almost all products. Recently, semitransparent reflective liquid crystal display devices have been mounted on most of these portable electronic devices.
The semitransparent reflective liquid crystal display device is provided with a reflection plate for reflecting light incident from an outside on the internal side or external side of a pair of transparent substrates constituting the liquid crystal display device, is further provided with a backlight on the back side thereof and, therefore, can be used while a reflective mode as a reflective liquid crystal display device using sunlight or an external illumination as a light source and a transmissive mode as a transmissive liquid crystal display device using light from the backlight as a light source are switched.
FIG. 19 is a diagram showing an example of the partial sectional structure of a conventional semitransparent reflective liquid crystal display device. This semitransparent reflective liquid crystal display device 50 includes a liquid crystal panel 50a having a configuration in which transparent electrode layers 53 and 54 are placed on respective counter-surface sides of a pair of glass substrates 51 and 52, liquid crystal orientation films 55 and 56 are further placed on these transparent electrode layers 53 and 54, respectively, and a liquid crystal layer 57 are placed between these orientation films 55 and 56.
A first phase difference plate 66 and a first polarizing plate 68 are laminated on the external side of one glass substrate 51 in that order from the substrate 51 side. A second phase difference plate 67 and a second polarizing plate 69 are placed sequentially on the external side of the other glass substrate 52, and a reflection plate 70 is attached on the external side of the second polarizing plate 69 with a transparent adhesive layer 70a therebetween.
In FIG. 19, reference numeral 65 denotes a sealing member for encapsulating the liquid crystal layer 57 between the glass substrates 51 and 52, and reference numeral 75 denotes a backlight placed on the underside of the reflection plate.
As shown in FIG. 19 and FIG. 20, for example, a concave and convex surface is formed on the surface of a resin film 71, a semitransparent reflection film 72 made of aluminum, etc., is further formed on this concave and convex surface using an evaporation method, etc., and, therefore, the reflection plate 70 is configured. The film thickness of this semitransparent reflection film 72 is specified to be within the range of 5 to 50 nm, and a part of light from the backlight 75 can be transmitted. This reflection plate 70 is attached while the surface on the semitransparent reflection film 72 side is faced toward the second polarizing plate 59 side.
The semitransparent reflective liquid crystal display device 50 having the aforementioned configuration is used as, for example, a display portion of a cellular phone. This semitransparent reflective liquid crystal display device 50 is operated in the reflective mode without lighting up of the backlight 75 when adequate external light is available and is operated in the transmissive mode with the backlight 75 being operated under circumstances where the external light is not available.
In the reflective mode, the light incident upon the first polarizing plate 68 is linearly polarized by this polarizing plate 68, and the polarized light is elliptically polarized by passing through the first phase difference plate 66, the liquid crystal layer 57, and the second phase difference plate 67. This elliptically polarized light is linearly polarized by passing through the second polarizing plate 69. This linearly polarized light is reflected at the reflection plate 70, is passed again through the second polarizing plate 69, the second phase difference plate 67, the liquid crystal layer 57, and the first phase difference plate 66, and is emitted from the first polarizing plate 68.
In the transmissive mode, the light emitted from the backlight 75 and passed through the semitransparent reflection film 72 is linearly polarized by the second polarizing plate 69, the polarized light is elliptically polarized by passing through the second phase difference plate 67, the liquid crystal layer 57, and the first phase difference plate 66. This elliptically polarized light is linearly polarized by passing through the first polarizing plate 68, and is emitted from the first polarizing plate 68.
Meanwhile, as display performances of liquid crystal display devices, in general, it is required that (1) resolution, (2) contrast, (3) luminance of screen, (4) visibility, for example, viewing angle of wide range, and the like are excellent.
However, regarding the conventional semitransparent reflective liquid crystal display device 50, since the second polarizing plate 69 has been placed between the reflection plate 70 and the liquid crystal panel 50a, in the reflective mode, problems arise as the incident light passes through the second polarizing plate 69 twice. These problems include the whole screen of the semitransparent reflective liquid crystal display device 50 becomes light green due to degradation of the spectral characteristic, contrast of the screen degrades and visibility is reduced.
Regarding the conventional semitransparent reflective liquid crystal display device 50, since the reflection efficiency of the reflection plate 70, on which the concave and convex surface has been formed, is reduced, the reflectance is reduced as a whole and, therefore, the need of the reflection plate for reflecting the incident light at a reflection angle of wider range is not adequately met. Consequently, regarding the semitransparent reflective liquid crystal display device 50 provided with the reflection plate 70 of this sort, problems arise in that the viewing angle is within the relatively narrow range of about 25 to 35 degrees and the luminance of the screen is not adequate.
Regarding the conventional semitransparent reflective liquid crystal display device 50, since the phase difference plates and the polarizing plates is provided by two plates, respectively, the number of parameters of various optical characteristics is increased and, therefore, optimization of each parameter is complicated. Especially, in the transmissive mode, the increase in luminance and the improvement in contrast of the screen is difficult to achieve.
Consequently, it is considered that the second phase difference plate 67 and the second polarizing plate 69 are removed, the first phase difference plate 68 is made of a laminated plate of two layers exhibiting two different optical characteristics as the phase difference plate, only one plate of the first polarizing plate 68 placed on the first phase difference plate 66 is used as the polarizing plate and, therefore, the white display is lightened when the selection voltage is applied. However, in such a semitransparent reflective liquid crystal display device, since the change merely consists of reducing both of the phase difference plate and the polarizing plate by one plate, the reflection efficiency of the reflection plate 70 remains poor. This means that both the light display and the dark display (black display) are lightened and, therefore, the contrast is reduced.
The present invention has been made in consideration of the aforementioned circumstances. Accordingly, it is an object of the present invention to provide a liquid crystal display device in which no phase difference plate and no polarizing plate are placed between a liquid crystal panel and a reflector placed on the outer surface side thereof and which has a wide viewing angle, high luminance, and high contrast.
In order to achieve the aforementioned object, the present invention has adopted the following configuration.
A liquid crystal display device according to the present invention is provided with a liquid crystal cell, in which a transparent electrode and an orientation film are placed on the inner surface side of one transparent substrate (a first transparent substrate) of/a pair of transparent substrates facing each other with a liquid crystal layer therebetween in that order from the one transparent substrate side, and a transparent electrode and an orientation film are placed on the inner surface side of the other transparent substrate (a second transparent substrate) in that order from the other transparent substrate side, first and second phase difference plates and a first polarizing plate formed sequentially on the outer surface side of the other transparent substrate, a reflector attached on the outer surface side of the one transparent substrate with an adhesive layer therebetween, and a third phase difference plate and a second polarizing plate formed sequentially on the outer surface side of the one transparent substrate more distal to the liquid crystal cell than the reflector. The reflector includes a metal reflection film formed on a base material. The base material has a surface with a plurality of concave portions. The metal reflection film includes a plurality of concave surfaces corresponding to the concave portions. The metal reflection film is attached to the liquid crystal cell, is more proximate to the first transparent substrate than the base material, and has a thickness of 5 to 50 nm.
According to such a liquid crystal display device, since the second polarizing plate is placed on the external side of the reflector including the metal reflection film having a film thickness of 5 to 50 nm, in a reflective mode, incident light is reflected by the metal reflection film and does not pass through the second polarizing plate and, therefore, spectral characteristics are not degraded, the color of the screen of the liquid crystal display device can be brought close to white, and the contrast ratio of the screen is improved so that it becomes possible to improve the visibility. In a transmissive mode, since light emitted from a backlight passes through the third phase difference plate and the second polarizing plate, passes through the metal reflection film as well and, furthermore, passes through the liquid crystal layer, the first and second phase difference plates, and the first polarizing plate, the light display (white display) is lightened while the dark display (black display) is darkened and, therefore, it becomes possible to improve the contrast ratio.
In particular, since the reflector is configured by forming the metal reflection film on the base material with the plurality of concave portions formed on the surface while the metal reflection film includes the plurality of concave surfaces corresponding to the concave portions, light condensing function is enhanced compared to that of the conventional reflection plate including concavities and convexities on the surface and, therefore, the reflectance can be increased. According to this, the light display in the reflective mode is lightened, the luminance and contrast ratio are improved and, therefore, superior display characteristics can be achieved.
Regarding the liquid crystal display device according to the present invention, the reflector is placed on the external side of the liquid crystal cell, and when the reflector is attached on the liquid crystal cell, adhesion can be performed at ambient temperature. Consequently, when the liquid crystal cell and the reflector are manufactured separately and, thereafter, the reflector is retrofitted to this liquid crystal cell, since thermal stress is not applied to the liquid crystal cell during manufacture of the reflector, and agents, etc., used during manufacture of the reflector do not fall on the liquid crystal cell, degradation of the liquid crystal cell can be prevented.
Preferably, the liquid crystal layer has a helical structure twisted 240 degrees to 250 degrees in the direction of the thickness thereof, the retardation (xcex94ndLC) of the liquid crystal cell is 600 nm to 800 nm, when the orientation direction a of the orientation film on the other transparent substrate side and the orientation direction b of the orientation film on the one transparent substrate side are viewed from the incident side of light, and the normal direction X between the orientation directions a and b passes at an angle half the interior angle formed by the cross-point O of the orientation directions a and b and the orientation directions a and b, the retardation (xcex94ndRF1) of the first phase difference plate adjacent to the other transparent substrate is 100 nm to 200 nm, an angle (xcfx86RF1), which a lagging phase axis xcex2 of the first phase difference plate forms with respect to the normal direction X, is 60 degrees to 100 degrees counterclockwise when viewed from the incident side of the light, the retardation (xcex94ndRF2) of the second phase difference plate adjacent to the first polarizing plate is 300 nm to 500 nm, an angle (xcfx86RF2), which a lagging phase axis xcex3 of the second phase difference plate forms with respect to the normal direction X, is 90 degrees to 140 degrees counterclockwise when viewed from the incident side of the light, the retardation (xcex94ndRF3) of the third phase difference plate adjacent to the one transparent substrate is 132.5 nm to 142.5 nm, an angle (xcfx86RF3), which a lagging phase axis xcex4 of the third phase difference plate forms with respect to the normal direction X, is 80 degrees to 110 degrees counterclockwise when viewed from the incident side of the light, an angle (xcfx86pol1), which an absorption axis xcex1 of the first polarizing plate forms with respect to the normal direction X, is 20 degrees to 70 degrees or 110 degrees to 160 degrees counterclockwise when viewed from the incident side of the light, and an angle (xcfx86pol2), which an absorption axis xcex5 of the second polarizing plate forms with respect to the normal direction X, is 23 degrees to 43 degrees counterclockwise when viewed from the incident side of the light.
In a liquid crystal display device with the above characteristics, the white display (light display) is further lightened and, therefore, it becomes possible to achieve an increase in luminance of the liquid crystal display device.
Preferably, the liquid crystal layer has the helical structure twisted 240 degrees in the direction of the thickness thereof, the retardation (xcex94ndLC) of the liquid crystal cell is 700 nm, when the orientation direction a of the orientation film on the other transparent substrate side and the orientation direction b of the orientation film on the one transparent substrate side are viewed from the incident side of light, and the normal direction X between the orientation directions a and b passes at the angle half the interior angle formed by the cross-point O of the orientation directions a and b and the orientation directions a and b, the retardation (xcex94ndRF1) of the first phase difference plate adjacent to the other transparent substrate is 170 nm, the angle (xcfx86RF1), which the lagging phase axis xcex2 of the first phase difference plate forms with respect to the normal direction X, is 80 degrees counterclockwise when viewed from the incident side of the light, the retardation (xcex94ndRF2) of the second phase difference plate adjacent to the first polarizing plate is 425 nm, the angle (xcfx86RF2), which the lagging phase axis xcex3 of the second phase difference plate forms with respect to the normal direction X, is 113 degrees counterclockwise when viewed from the incident side of the light, the retardation (xcex94ndRF3) of the third phase difference plate adjacent to the one transparent substrate is 137.5 nm, the angle (xcfx86RF3), which the lagging phase axis xcex4 of the third phase difference plate forms with respect to the normal direction X, is 90 degrees counterclockwise when viewed from the incident side of the light, the angle (xcfx86pol1), which the absorption axis xcex1 of the first polarizing plate forms with respect to the normal direction X, is 42 degrees counterclockwise when viewed from the incident side of the light, and the angle (xcfx86pol2), which the absorption axis xcex5 of the second polarizing plate forms with respect to the normal direction X, is 33 degrees counterclockwise when viewed from the incident side of the light.
In a liquid crystal display device with the above characteristics, the white display (light display) is further lightened and, therefore, it becomes possible to achieve an increase in luminance of the liquid crystal display device. In particular, according to the aforementioned liquid crystal display device, the display color of the white display (light display) can be brought closer to white and, therefore, it becomes possible to improve the color purity and the visibility.
Preferably, the liquid crystal layer has the helical structure twisted 240 degrees to 250 degrees in the direction of the thickness thereof, the retardation (xcex94ndLC) of the liquid crystal cell is 600 nm to 800 nm, when the orientation direction a of the orientation film on the other transparent substrate side and the orientation direction b of the orientation film on the one transparent substrate side are viewed from the incident side of light, and the normal direction X between the orientation directions a and b and which passes at the angle half the interior angle formed by the cross-point O of the orientation directions a and b and the orientation directions a and b, the retardation (xcex94ndRF1) of the first phase difference plate adjacent to the other transparent substrate is 100 nm to 200 nm, the angle (xcfx86RF1), which the lagging phase axis xcex2 of the first phase difference plate forms with respect to the normal direction X, is 60 degrees to 100 degrees counterclockwise when viewed from the incident side of the light, the retardation (xcex94ndRF2) of the second phase difference plate adjacent to the first polarizing plate is 300 nm to 500 nm, the angle (xcfx86RF2), which the lagging phase axis xcex3 of the second phase difference plate forms with respect to the normal direction X, is 90 degrees to 140 degrees counterclockwise when viewed from the incident side of the light, the retardation (xcex94ndRF3) of the third phase difference plate adjacent to the one transparent substrate is 120 nm to 130 nm, the angle (xcfx86RF3), which the lagging phase axis xcex4 of the third phase difference plate forms with respect to the normal direction X, is 48 degrees to 68 degrees counterclockwise when viewed from the incident side of the light, the angle (xcfx86pol1), which an absorption axis xcex1 of the first polarizing plate forms with respect to the normal direction X, is 20 degrees to 70 degrees or 110 degrees to 160 degrees counterclockwise when viewed from the incident side of the light, and the angle (xcfx86pol2), which an absorption axis xcex5 of the second polarizing plate forms with respect to the normal direction X, is 3 degrees to 23 degrees counterclockwise when viewed from the incident side of the light.
In a liquid crystal display device with the above characteristics, the white display (light display) is further lightened and, in addition, the black display (dark display) is further darkened, so that it becomes possible to increase the contrast ratio.
Preferably, the liquid crystal layer has the helical structure twisted 240 degrees in the direction of the thickness thereof, the retardation (xcex94ndLC) of the liquid crystal cell is 700 nm, when the orientation direction a of the orientation film on the other transparent substrate side and the orientation direction b of the orientation film on the one transparent substrate side are viewed from the incident side of light, and the normal direction X between the orientation directions a and b passes at the angle half the interior angle formed by the cross-point O of the orientation directions a and b and the orientation directions a and b, the retardation (xcex94ndRF1) of the first phase difference plate adjacent to the other transparent substrate is 170 nm, the angle (xcfx86RF1), which the lagging phase axis xcex2 of the first phase difference plate forms with respect to the normal direction X, is 80 degrees counterclockwise when viewed from the incident side of the light, the retardation (xcex94ndRF2) of the second phase difference plate adjacent to the first polarizing plate is 425 nm, the angle (xcfx86RF2), which the lagging phase axis xcex3 of the second phase difference plate forms with respect to the normal direction X, is 113 degrees counterclockwise when viewed from the incident side of the light, the retardation (xcex94ndRF3) of the third phase difference plate adjacent to the one transparent substrate is 125 nm, the angle (xcfx86RF3), which the lagging phase axis xcex4 of the third phase difference plate forms with respect to the normal direction X, is 58 degrees counterclockwise when viewed from the incident side of the light, the angle (xcfx86pol1), which the absorption axis xcex1 of the first polarizing plate forms with respect to the normal direction X, is 42 degrees counterclockwise when viewed from the incident side of the light, and the angle (xcfx86pol2), which the absorption axis xcex5 of the second polarizing plate forms with respect to the normal direction X, is 13 degrees counterclockwise when viewed from the incident side of the light.
In a liquid crystal display device with the above characteristics, the white display (light display) is further lightened and, in addition, the black display (dark display) is further darkened, so that it becomes possible to further increase the contrast ratio of the liquid crystal display device. In particular, according to the liquid crystal display device, the display color of the white display (light display) can be brought closer to white and, therefore, it becomes possible to improve the color purity and the visibility.
Preferably, the Nz coefficient represented by Formula (1) of the first phase difference plate is xe2x88x920.5 to 2.0, and the Nz coefficient represented by Formula (1) of the second phase difference plate is xe2x88x920.5 to 2.0.
Nz=(nxxe2x88x92nz)/(nxxe2x88x92ny)xe2x80x83xe2x80x83Formula (1) 
(In the formula, nx denotes a refractive index in the X axis direction of the phase difference plate, ny denotes a refractive index in the Y axis direction of the phase difference plate, and nz denotes a refractive index in the Z axis direction of the phase difference plate.)
According to such a liquid crystal display device, the range in which contrast is excellent is extended in the vertical and horizontal directions of the display surface. Consequently, the viewing angle is increased in the vertical and horizontal directions of the display surface and, therefore, a liquid crystal display device having superior visual angle characteristic can be achieved.
Preferably, the liquid crystal display device according to the present invention is the liquid crystal display device, wherein the Nz coefficient represented by the Formula (1) of the first phase difference plate is 0.5, and the Nz coefficient represented by the Formula (1) of the second phase difference plate is 0.3.
According to such a liquid crystal display device, the range in which contrast is excellent is further extended in the vertical and horizontal directions of the display surface. Consequently, the viewing angle is further increased in the vertical and horizontal directions of the display surface and, therefore, further superior visual angle characteristic can be achieved.
Preferably, in the liquid crystal display device according to the present invention the plurality of concave surfaces of the metal reflection film are formed continuously and each concave surface comprises a part of a sphere.
According to such a liquid crystal display device, when the plurality of concave surfaces of the metal reflection film are continuous and each concave surface has the shape of a part of a sphere, the reflection efficiency of the light can be improved remarkably compared to that heretofore attained. Consequently, it is possible to thin the metal reflection film in order to improve the translucency of the liquid crystal display device and, therefore, well-lighted display as a transmissive liquid crystal display device can be achieved as well as an improved reflective liquid crystal display device. Thus, both a reflective type and transmissive type well-lighted display can be achieved.
Preferably, in the liquid crystal display device according to the present invention the depths of the plurality of concave portions are 0.1 xcexcm to 3 xcexcm, the distribution of the angles of inclination of the concave portion inner surfaces is xe2x88x9230 degrees to +30 degrees, and the pitches between adjacent concave portions are 5 xcexcm to 50 xcexcm.
According to such a liquid crystal display device, since the surface shape of the base material can be optimized, it is possible to more efficiently reflect the light incident from the outside and, therefore, further well-lighted display can be achieved.
Preferably, in the liquid crystal display device according to the present invention the plurality of concave portions include a first longitudinal section and a second longitudinal section, each passing through the deepest point of the concave portion, the shape of the inner surface of the first longitudinal section is composed of a first curve from a first peripheral portion of the concave portion to the deepest point and a second curve from the deepest point to a second peripheral portion of the concave portion extending from the first curve, and the average value of the absolute values of the angles of inclination of the first curve with respect to the base material surface is larger than the average value of the absolute values of the angles of inclination of the second curve with respect to the base material surface, while the second longitudinal section is orthogonal to the first longitudinal section, and the shape of the inner surface thereof is composed of a shallow type curve and deep type curves existing on both sides of the shallow type curve and having radii of curvature smaller than that of the shallow type curve.
In the present specification, although it is not specifically limited which direction of longitudinal section is assumed to be the first longitudinal section, it is desirable that the longitudinal section in the vertical or fore-and-aft direction when viewed from an observer is assumed to be the first longitudinal section.
According to such a liquid crystal display device, the inner surface shape of the concave portion is formed into a curve which comprises the first curve and the second curve, the boundary therebetween being the deepest point in the first longitudinal section, and in which the average value of the absolute values of the angles of inclination of the first curve with respect to the base material surface is larger than the average value of the absolute values of the angles of inclination of the second curve with respect to the base material surface. That is, the inclination of the first curve is relatively steep, the inclination of the second curve is relatively gentle, and the second curve is longer than the first curve.
Consequently, the quantity of light reflected at the surface in the periphery of the second curve is more than that of light reflected at the surface in the periphery of the first curve. That is, reflection is enabled such that the luminous flux density in the direction of the specular reflection with respect to the surface in the periphery of the second curve is high. Therefore, when the directions of respective first curves of the concave portions are arranged in the specified direction (single or a plurality of specified directions), the reflection intensity in the specified direction can be increased as the total reflector.
Furthermore, since each inner surface shape of these concave portions in the second longitudinal section orthogonal to the first longitudinal section is formed to include the shallow type curve and the deep type curves existing on both sides of the shallow type curve and having small radii of curvature, the reflectance nearly in the direction of the specular reflection can be increased. It is desirable that the deep type curves exist evenly on both sides of the shallow type curve.
Consequently, regarding the total reflection characteristics in the first longitudinal section, the reflectance has a peak at an angle of the specular reflection and, in addition, the reflectance toward the direction of reflection by the surface in the periphery of the second curve is increased. That is, it is possible to achieve a reflection characteristic which can condense the reflected light moderately in the specified direction while the reflected light in the direction of the specular reflection is ensured adequately.
Preferably, in the liquid crystal display device according to the present invention the plurality of concave portions are formed such that each of the first longitudinal sections and the second longitudinal sections is in the same direction, and each of the first curves is orientated unidirectionally, and the reflector is placed such that the first curves in respective concave portions locate above the second curves when viewed from the observer.
That is, the first curves of respective concave portions are orientated unidirectionally and, in addition, the second curves of respective concave portions are also orientated unidirectionally.
According to such a liquid crystal display device, the reflectance in the direction of reflection caused by the surface in the periphery of the second curve is increased. That is, it is possible to moderately condense the reflected light toward the specified direction.
When all the first curves in concave portions are located above the second curves when viewed from the observer, in general, external light, etc., primarily incident from above is shifted toward the direction of the normal to the base material surface rather than the direction toward the feet of the observer.
Since the external light, etc. primarily incident from above when viewed from the observer efficiently enters into the surface in the periphery of the second curve, the quantity of the reflected light is increased as a whole.
Furthermore, the quantity of light in the direction of the specular reflection can be ensured adequately by the reflection from the shallow curve in the second longitudinal section.
Consequently, the quantity of light reflected in the direction of the line of sight of the observer is increased and, therefore, a reflective liquid crystal display device with a well-lighted display at the practical point of view is realized.
Preferably, in the liquid crystal display device according to the present invention the angles of inclination of the first curve and the second curve become zero with respect to the base material surface at the position where they are in contact with each other.
According to such a liquid crystal display device, since the whole concave portion inner surface can be formed gently, it is possible to avoid reduction of the quantity of reflection in the direction of the specular reflection.
Preferably, in the liquid crystal display device according to the present invention the depths of the plurality of concave portions are 0.1 xcexcm to 3 xcexcm and are formed randomly.
When the depth of concave portion is less than 0.1 xcexcm, scattering effect of light is inadequate. When exceeding 3 xcexcm, the thickness of the base material for realizing this depth becomes excessively large leading to problems during manufacture as well as a product that is excessively thick, weighty, and generally inconvenient. When the depths of the plurality of concave portions are formed on a random basis, occurrence of the moirxc3xa9{acute over ( )}pattern due to interference of light (which is likely to occur when the depths of the concave portions are formed regularly) is prevented, peak-like condensation of the quantity of reflected light at a specified visual angle is alleviated and, therefore, change of the quantity of reflected light in the visual angle becomes gentle.
Preferably, in the liquid crystal display device according to the present invention the plurality of concave portions are disposed randomly and adjacent to each other.
When the interval between concave portions is large, since a flat surface is disposed between the concave portions, plane reflection is increased, and adequate diffuse reflection cannot be achieved in a limited pixel region. Consequently, the concave portions are preferably formed adjacently to each other. Since the moirxc3xa9{acute over ( )}pattern occurs when the concave portions are arranged regularly, the concave portions are preferably arranged randomly.
Preferably, in the liquid crystal display device according to the present invention the reflectance reaches a peak at the angle of the specular reflection with respect to the metal reflection film surface, the integral of reflectance within the range of the reflection angle smaller than the angle of the specular reflection and the integral of reflectance within the range of the reflection angle larger than the angle of the specular reflection are different, and the range of the reflection angle of the total reflector in which the integral of reflectance is large is above the angle of the specular reflection with respect to the metal reflection film surface when viewed by the observer.
According to such a liquid crystal display device, and according to the present invention, when the usual viewing angle of the observer deviates from the direction of the specular reflection, a reflector is formed that reflects light primarily in the direction of the usual viewing angle while the reflected light in the direction of the specular reflection is ensured.
In general, external light, etc., primarily incident from above can be shifted toward the direction of the normal to the base material surface rather than the direction toward the feet of the observer.
Consequently, for example, when used as a display device of a cellular phone and a notebook computer, the quantity of light reflected in the direction of the line of sight of the observer is increased and, therefore, a reflective liquid crystal display device with a well-lighted display at the practical point of view is realized.
In the liquid crystal display device according to the present invention, a color filter may be placed between the one transparent substrate constituting the liquid crystal cell and the transparent electrode placed on the inner surface side thereof.